A flat panel display possesses advantages of being ultra thin, power saved and radiation free and has been widely utilized. The present flat panel display devices at present mainly comprise the Liquid Crystal Display (LCD) and the Organic Light Emitting Display (OLED).
Thin Film transistors (TFT) are important components of a flat panel display device. The TFTs can be formed on a glass substrate and a plastic substrate and generally employed as switch elements and driving elements utilized such as flat panel displays, LCDs, OLEDs and et cetera. As regarding of LCD, the Active Matrix Liquid Crystal Display utilizes GOA (Gate Drive On Array) circuit constructed with a plurality of TFTs is required to integrate the gate driver (Gate Drive IC) on the thin film transistor array substrate to achieve the scan line by line for driving the liquid crystal panel. For the Active Matrix OLED (AMOLED), the pixel compensation circuit constructed with a plurality of TFTs is required to implement compensation to the threshold voltage of the drive thin film transistor to make the display brightness of the AMOLED even.
With the global competition of the display panel grows more bitter, the demands of all the display makers for the narrow frame, high resolution get higher and higher. Particularly, in the mobile display device field, the present display panel frame has been narrowed to be under 2 mm, and the Pixels Per Inch (PPI) has already reached up higher than 500. For the design of the display panel, the narrower frame means smaller GOA arrangement space. The higher PPI means a smaller sub pixel area. Under this circumstance that the process ability is unchanged, the circuit effective arrangement area gets smaller. Particularly for the AMOLED display panel, one sub pixel generally comprises 2-7 TFTs. Thus, the higher demand is proposed for the circuit arrangement.
The present GOA circuit and AMOLED pixel compensation circuit generally relate to the condition that one control signal line controls two TFTs. As shown in FIG. 1, both the gates of the first, second thin film transistors T10, T20 are electrically coupled to one control signal line G, i.e. both the first, second thin film transistors T10, T20 are controlled by the control signal line G; FIG. 2 is a TFT arrangement structure diagram of the circuit shown in FIG. 1. Both the source S10, the drain D10 of the first thin film transistor T10 are formed on the patterned active layer SC. Similarly, both the source S20, the drain D20 of the second thin film transistor T20 are formed on the patterned active layer SC. The same gate layer Gate coupled to the one control signal line controls the first, second thin film transistors T10, T20 at the same time. Because all the source S10, the drain D10 of the first thin film transistor T10 and the source S20, the drain D20 of the second thin film transistor T20 are formed on the patterned active layer SC. The first, second thin film transistors T10, T20 can only arranged in parallel and in interval along the pattern alignment direction of the active layer SC. The occupied arrangement space is larger, which goes against the development of the narrow frame and high resolution of the display panel.